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Summit F. A. Q.

Summit FAQ
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Personal note: The summit origin starts with the revo/e-revo platform with specific additions to make it much more off road worthy. These additions place it very close into the crawler category. Though there are many details which keep the summit from becoming a "true crawler" it still does very well as its purpose: a hybrid. With this background I would like to encourage summit owners to push the envelope. Look beyond the standard erevo bolt-ons and incorporate into your summit additional and original off roading / crawling ideas. Traxxas gave us a great start - two speed transmissions (high and granny-gear low) and remote lockable diffs (an industry exclusive), lets keep pushing and share the results. There is an e-revo FAQ on the e-revo boards, which I do not plan to duplicate. Since both the e-revo and summit platforms are the same I suggest seeking additional details from there. This FAQ will cover most of the basics but I will make a strong attempt to add to it original idea shared by summit owners, common aftermarket options, and reliable upgrades with links to "how to"s by other summit owners. This FAQ will be link-heavy so if you see a link to your build or a note from your posting, consider that a thank you from me and all the other summit owners.

Realize 85% of the summit is really just an erevo, and since the erevo has been out longer and has a larger following, much info for the summit can be found on the erevo boards. In Fact here is the FAQ for the Erevo which has a lot of great summit related info as well (no use putting up DUPLICATE INFO)-

the main (basically only) differences between the E-revo and Summit are:

1) summit comes stock with extended rear arms
2) summit has the 2 speed tranny with servo (but one can buy/put a second gear into an erevo tranny and have the same)
3) summit has the locking diffs both front and rear with the dual servos
4) Front/rear bumpers with LEDs and wiring
5) single plate motor mount with a titan 775 motor as opposed to dual plate and two titan 550 motors
6) The erevo has stock 14mm hexes while the brushless erevo (ERBE) and the summit both have the 17mm hexes
7) summit has the 4 beefed up axles and differentials which (the diff) hangs longer on one side than the other (main reason why Traxxas steel CVDs aren’t recommended for the summit - see MIP)
8) summit stock gearing 14/68 pinion/spur (E revo 19/68, E Revo brushless 18/68)
9) summit comes stock with the long travel (LT) rockers and a longer shock barrel (more grooves) which gives the summit its taller stance
10) older versions (non 2.4ghz) has a t-lock mechanism in the receiver box which controls the locking of the diffs
11) the chassis are identical with the summit having a small hole/cut-out at each end for the locking diffs to fit properly and of course hardware to secure the additional servos

2. EVX2 speed controller
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This is Traxxas's second iteration of the EVX electronic speed controller (esc), with the main upgrade being the increased voltage handling. The original boasted 14.4 volts and was a Novak design, the EVX2 has a power rating of 16.8 volt, is waterproof and still retains the easy 3 mode programming features of the original, (sport mode, race mode (no reverse), and 50% power training mode). Many accounts have been made regarding the EVX2 and it’s waterproof ability. Personal experience, the esc is waterproof to a degree.
Like many others after a long bout with water I somehow lost the ability to go into reverse. Luckily the next day once the esc dried out reverse returned, but this is not always guaranteed. The EVX is also capable of handling lipo (lithium) batteries. BUT BE WARNED repeat BE WARNED although the esc can handle lipo batteries there is no internal low voltage cut off within the esc. In other words the esc will literally drain your lipo batteries to death (which is usually somewhere below 3.0 volts per cell). So use of lipo batteries is suggested only with a low voltage alarm (LVA) or a low voltage cut-off (LVC) both of these items are fairly cheap, should be considered requirements with lipo batteries and are discussed in a later section. The EVX2 is wired internally in series and can handle a 7.4 volt (2s) lipo on either plug (for a total of 4s). With extreme care it can also handle up to 5s if the batteries are attached as a 2s battery connected to the BEC (battery elimination circuit), and the 3s battery connected to the NON BEC side.

To determine your BEC side/plug follow this procedure:
with the esc off and all batteries unplugged
____________________________________________
1. Connect your 2s lipo battery to one plug
2. Turn on the esc - watch the light closely
3. If the green light flashes on briefly then this is your BEC side.
the other connection should be your NON BEC side
I suggest testing the other side with a 2s lipo battery as well to be certain.
Usually the BEC side will have the red tag attached to it. If it does not then attach something to it now to identify your BEC side in the future. Never connect a 3s lipo to the BEC side. To reiterate, to use 5s lipo, attach the 2s to the BEC side and the 3s to the non BEC side only. Of course this is not supported by Traxxas so use cautiously and at your trucks peril. But personally I can tell you it does work, will add 5-10 mph to your top speed and will lead to an early death to your stock motor due to heat and excessive speed, works much better with a DeWalt motor.

+++ Note: When using a 3s lipo with a 2s lipo both lipos should be of the same mah, same discharge rating or "C" rating, both should have an equal charge and both lipo batteries should be of the same name brand (each manufactures batteries have slightly different specs no matter what they advertise, so the more identical the batteries the better).
You have been warned. But if you USE COMMON SENSE the dangers will be minimized Before using lipo batteries read the lipo section further down in the post for further precautions.

+++ SPECIAL NOTE: The BEC side connector of the esc will uses more energy than the non BEC connector; therefore the esc will always drain the battery connected to the BEC side faster. So if an lvc/lva is used it should be connected to the batter on the BEC side. This is one reason it important to charge you batteries equally.

The EVX2 is fairly robust and smooth can handle 550 sized brushed motors, 700 size brushed motors, and even dewalt drill brushed motors. Of course it can be powered by 6 and 7 cell nimh packs with ease, and is usually only replaced when the owner desires to install a brushless system.

3. Lipo, A123 batteries (stolen from suicide neal's erevo faq)
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Lipo = lithium polymer. They have a nominal (resting) voltage of 3.7v per cell, and a fully charged voltage of 4.2, but unlike Nimh cells, you can actually select the fully charged voltage provided you have a suitable charger; this is handy for escs that don't like peaked voltages sometimes (MambaMaxx and Quark 125b for example).
When charging, and discharging (running them in a vehicle), the individual cells in a pack can become out of balance. This means in a 2s pack for example (s = cells in series), one cell can read slightly higher or lower than the other, and over time this difference can become large enough to mean that one cell becomes over-discharged during use; it is important not to discharge them below 2.8v per cell, but 3.0v is a safer level.

This is where the LVC device comes into play, as it cuts the throttle, or reduces power when the cells have drained down to whatever the cut-off voltage is set to. Some LVCs have adjustable voltage settings, and cutoff type (reduced power, warning light, warning buzzer, total shut-off etc), depending on the application; you wouldnt want to loose all power with a plane or heli for example...
When charging lipos, the balancer device is used to keep the voltage equal in all the cells of a pack- it can be a balancer that works along with the charger, separate from the charger, or you charge through the balancer. The end result is the same though- cells with a lower voltage get extra charge, whilst cells with a higher voltage get drained a little to keep them in line with the others. This is what the little white plug is for that you see sticking out of lipo cell packs, it is the balancing plug/tap.
The lipo's battery chemistry requires a special technique, called the CC/CV method (constant current/constant voltage).
Basically, the charger will pump in a high current (amps) until the cells reach ~4.2v, then they will drop the current but maintain the voltage level until the cells reach and stay at 4.2v, at which point they are fully charged. Over charging is very dangerous, as lipo cells contain alot of energy, and overheating them can be a serious firehazard, hence the items called 'lipo sacks' that should be used to contain any possible damage caused by a burning lipo. The chances of that are rare these days though, and only idiots on youtube tend to burn up lipos for fun.
Lastly, the C rating thing. This refers to a lipos maximum discharge rating, and is a multiple of its capacity. For example:

A 20c 5000mah pack can put out 100amps.
A 10c 8000mah pack can put out 80amps.

Choosing the right capacity and C rating is important for any given application, and should be based on how many amps your chosen motor can draw at maximum load.
For example, the feigao XL motors tend to draw about 80-100amps at peak current levels, so you should select a battery that can supply at least 80amps continuous. Generally though, the motors pull a continuous current of about 10-20amps or thereabouts, so the battery wont see very high drain rates for the whole run, otherwise it would soon over-heat and 'puff'. Once a battery puffs, its pretty much toast, though individual cells that are still okay can be salvaged- a 5s lipo can be reconfigured into a smaller pack of 4s etc.
With the E-Revo, you are limited to a 8000mah 2s lipo, or 5000mah 3s lipo in each battery compartment, though specific sizes of packs vary, see below:

A123 cells have a very high energy density like Lipo cells, but are inherently safer and 99% indestructible, so do not have to be used with an LVC (low voltage cut-off) device, and can be charged much quicker given the correct equipment is used. Their resting voltage is 3.4v, which makes a 5s configuration ideal for most applications that would normally use 12~14 Nimh cells, or 4s lipo. The downside is that they are limited to 2300mah or so of capacity, so ideally should be ran in a parallel formation such as 5s2p (2 five cell packs connected in parallel to double the Mah capacity but maintain the same voltage as 5 cells). They can be purchased easlily by buying a Dewalt 36v battery pack on Ebay, and then following one of the online tutorials which demonstrate how to turn them into RC packs. Mounting them in the E-revo requires some fairly drastic dremel work however.

4. Low voltage cut offs and alarms - LVA / LVC
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As mentioned in the EVX2 section, if you use lipo batteries on the stock esc
you WILL NEED either a low voltage alarm or a low voltage cut off.

Low Voltage Alarm
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Since the stock esc lacks any type of lipo protection in order to save
your lipo batteries from a hot swollen death you will need a low voltage alarm
(LVA). An lva is simply a circuit board which you simply plug into the balance
port of your lipo battery whose sole purpose is to monitor the voltage level of
your battery. When your lipo voltage dips down to 3.2 the lva will trigger a
buzzer or beeper to inform you to stop running your truck and re-charge your
batteries. Basic lva units cost from $3 to $7 and are a great insurance device
for your $30 lipo battery. Fancier versions may have adjustable cut off levels
(most lvas are factory set to buzz at 3.0 - 3.2volts, with the danger level at
roughly 2.8volts), and fancier ones yet may even tell you digitally (or via
LEDs) the exact voltage of your lipos. They are plentiful on Ebay. Note that a
lva will not stop you truck from driving. It will only tell you when its time
to stop. It’s up to you to actually stop running your truck before you kill your
lipo batteries.

Low Voltage Cut-off
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A step up from the lva is the low voltage cut off (LVC) (or lipo
cut-offs). An lvc is a circuit board which is wired between your esc and your
lipo battery. The lvc, instead of sounding an alarm when the voltage goes low,
will actually stop you from driving your truck. Some will simply cut the power
while others will make your truck stutter badly upon acceleration. Either way it
should clearly inform you when your battery is low and should disallow your
truck from being driven further. Again just like lvas some lvcs will have
adjustable cut off levels (3.2volts is usually suggested) and may have a
digital display. The most common lvc appears to be the Novak smart stop. Much
debate has been involved whether the proper Novak smart stop is the 4s or the
2s version. Due to the fact that the 2s BEC side of you EVX2 will consume
energy faster than the non-BEC side it has been decided by most that the 2s
Novak smart stop is the better choice for the EVX2. Kershaw Designs also sell
lvcs

IMPORTANT NOTE: Due to the fact that the BEC side of your EVX2 will drain the
battery voltage faster than the non BEC side your lva or lvc should be attached
to the BEC connector or to the lipo battery that will be connected to the BEC
connector. Both lipo batteries should be of the same mah and have similar
starting voltages to avoid over-discharging the non bec lipo by accident.

5. Transmission
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The summit transmission is dual geared wonder. It should not be compared to the automatic two speed shifting transmission of the revo 3.3 or the manual two speed shifter of the original e-maxx. Both of these trannies are intended for speed use, driving in 1st gear then shifting into 2nd gear as the speed builds. The summit tranny rather than being thought of as a 2 speed it should be thought of a low gear and high gear. Due to the wide separation of the low gear and the high gear, shifting on the run is not recommended. The tranny makes the summit a serious player in the off road game.
The low gear allows for extreme delivery of slow and controlled torque for grueling rock and hill climbing. The gearing ratio in high gear is 25.3:1 good for speeds up to 22 mph. (pinion and spur gear will affect final gear ratio) For comparison the e-revo has a gear ratio of 18.83:1 (30ish mph) and the brushless edition has 18.67:1 (45+mph). But speed is not the summits tranny's forte. The tranny really shines in low gear coming in at an EXTREME LOW of 70.18:1, simply great for crawling.

So as you can see the summits tranny compares well to not only true crawlers but also real life (Jeep) off road vehicles. So am I saying the summit is a true rock crawler? Of course not. But this is more fodder you can throw in the face of your nay sayer crawler friends (and they don’t have a high gear to shift into for bashing speeds). This low gear, paired with the high torque Titan 775 motor results in the unstop ability of the summit. The transmission features a Revo spec slipper assembly which allows for the usage of spur gears ranging from 54tooth up to 68tooth that comes as standard in 32p (MOD 0.8).Stock gearing in the summit is 14 pinion, 68 spur with an optional 18t pinion gear included in the summit package.
The summits transmission is externally identical to the e-revo's tranny, in fact Traxxas sells a kit with which you can install a 2nd lower gear into an e-revo's tranny. The kit has two optional gears, one low gear for racing and an optional lower gear (same as the summit) for off road crawling. Of course a servo and linkage is included for shifting purposes. And no the summit's tranny will not fit into the chassis of a revo 3.3 and nor vice versa, but an adapter plate is simple to fabricate. A common problem with the summits tranny is the steering linkage sticking and the tranny not shifting smoothly. In the bottom of the tranny is a small bearing (bead) and screw which can be manipulated to allow for smoother shifting. see links below

6. Suspension, arms, and axles with upgrades
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The stock summit suspension is a direct replica of the e-revo and revo
design, inbound shocks with a cantilever swinging rocker design. This design is
popular in formula 1 race cars and certain high level Porsches. Originally
designed for the revo 2.5 it does well in soaking up bumps and keeping the
wheels firmly planted on the ground. It creates a smooth and controlled rebound
action during racing and did well, propelling the revo platform to several ROAR
racing championships. But what about true off roading? Wonderful. The
adjustability which allows for a higher stance, stiffer springs and longer
rockers make this one time racing suspension into a hill crawling highly
flexible off-road setup.
The summit come stock with the long travel rockers and yellow shocks
in the rear. While at high speeds the summit has a tendency to squat under
power. Actually this appears a hereditary trait being shared by the entire revo
family. This is commonly solve by placing yellow springs in the rear of the
summit in place of the orange springs. This problem can also be solved by
preloading (winding up) the shock collars but this technique will limit the
rear flexibility and makes for a much stiffer ride. The stock arms and very
tough and rarely needs replacing. If replacements are needed RPM arms are a
popular choice.
Due to the fact the summits locking differentials overhangs to the
right side, shaving of the RPM arms cross beam will be required to assure
proper fit and to retain full flexibility. RPM arms are a slight bit softer
than the stock arms but allows for more flexibility and less breakage This
softer material also allow the pivot ball to pop out more often (especially
during crashes). Once a pivot ball pops out of the suspension arm the internal
threads will strip allowing the pivot ball to pop out easier and easier with
future crashes. One solution is the use of plumbers tape on the threads of the
pivot ball, another is the drilling of a small hole in the arm and the
placement of a grub screw to hold the pivot ball in place.
The wheel axles are a big upgrade from the previous revo/e-revo style
axles. Namely the metal cvd-style joints on each end, as opposed to the plastic
joint of the e-revo. The attaching ends of the sliding plastic portion of the
axle is a full supportive circle as opposed to the open two pronged "U" of the
e-revo axles. All for the better handling of low end torque. Yes both e-revo
and summit axles are interchangeable but the far better axle belongs to the
summit. Many people ask about metal axles (cvds). Traxxas offers only metal
center axles (although the plastic center axles hold up well). The standard
e-revo metal cvds do not allow for the one side overhang of the summit's
locking differential (making the cvd too long to fit on the right side) and
with the extreme high/angle of the summits suspension with the long travel
rockers the cvd has a tendency of popping/sliding out of the side that does
fit.
MIP has developed metal CVDs (MIP splined cvd kit for traxxas summit)
which duplicates the sliding/adjusting effect of the original summit axles but
reviews are mixed with some stating indestructible and others posting pictures
of broken MIP pieces. For the price tag ($96 for the set) is a bit high for
most to take a chance.

-LT rockers have 120mm of suspension movement, 90mm for the others.
-Progressive 1 rockers are the least progressive feel, very soft throughout the
entire up travel range.
-Progressive 2 rockers is a little bit stiffer toward the end of the
suspension's up travel.
-Progressive 3 rockers get quite a bit stiffer, starting at about mid-travel, and remains stiffer through the rest of the suspension up travel.

7. Locking Differentials
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Traxxas created an industry first with its remote locking differentials on an RTR vehicle (there is one other company who sells remote locking diffs but it’s an incomplete kit). Differentials, or diffs, are the key component in transferring power from the main drive train to the wheels themselves. Within each diff is a pinion and spider gear. These gears mesh together at a 90 degree angle as power is transferred to the wheels. Inside these sealed diffs is a silicone fluid which not only lubricates the gears but also aides in the amount of power each opposing wheel will receive. The thicker the silicone fluid (or diff fluid) the more equally the power will be distributed.
Even though equal power distribution sounds great, in vehicles it can have adverse effects. While turning corners the outer wheels must travel a greater distance to complete the turn. For this to be accomplished smoothly the outer wheel must rotate at a greater speed than the inner wheel. So in this case a thinner diff fluid, which transfers power unequally, (allows for more slippage within the diff) will accomplish this feat without the two wheels fighting to roll at the same speed. The summit diffs contain this fluid but also a mechanical locking device which forces both wheels to rotate at the identical speed, this is fantastic for getting power to the ground, climbing, greater traction and driving in straight lines, but will greatly hinder the vehicle during sharp turns and maneuvers.
Early summits had an issue with the output shaft on the side of the T-Lock mechanism within the diff breaking (part no 5678). But Traxxas quickly fixed the issue with a stronger metal and issued free replacement parts to summit owners who experienced this type of breakage. It is strongly suggested to come to a complete stop before locking your diffs, and then drive forward slowly a few inches to allow the diff gears to engage properly. As diffs get older the grind of metal gear on metal gear will inevitably lead to loosening of the engagement point and loosening of the differential. At or before this point many people will "shim" their diffs. Shimming your diff quite simply is placing small washers around the base of the pinion gear forcing the pinion gear to mesh tighter with the internal diff gears, essentially removing the excess space between the gear's teeth. The tighter the teeth engagement or mesh the less chance of breakage.

Tid Bits and notes:
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- In stock form the front diff locks before the rear diff to simulate a dig effect (whereas the front wheels PULLS the vehicle over an obstacle without the rear wheels PUSHING the vehicle up the obstacle possibly causing the vehicle to flip backwards)
- Which diff locks first can be changed by switching the A and B plugs of the T-lock controller inside the rx box. newer 2.4 GHz summit owners will switch the diff locking servo plug in locations.
-From manual Traxxas Model 5607 (page 24):
"From the factory, both of Summit’s differentials are filled with SAE
100,000W viscosity silicone oil. Only use silicone oil in the differentials.
Traxxas offers SAE 10,000W, 30,000W and 50,000W viscosity oil to tune
the action of the differentials. Lower-viscosity oil allows the differential
to operate more freely. If most of your driving is done at high speed or
on high-traction surfaces, filling the differentials with lower-viscosity
fluid may improve handling. The differentials must be removed from
the vehicle and disassembled to change/replace oil."
-Some may note that the Traxxas website says that the stock diffs are filled with 30k silicone oil but Traxxas insiders have confirmed 100k
-the locking diff can be replicated by using very heavy diff oil (500k)
or by inserting spools Traxxas part #5381X (spool). But the heavy diff oil will not completely lock the diff and the spool cannot be unlocked and will greatly widen your turning radius.

8. Motors with upgrades and options
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The stock titan 775 motor (Mabuchi RS 775vc/wc family) is strong and torque filled and when maintained will last a long time but once its dead its dead. Lipos tend to run the titan beyond its natural intended speed and temperatures which many time leads to its early (smoky) death. Like most all motors it is water proof but will still need to be dried, cleaned and properly lubricated after long water sessionshttp://www.mabuchi-motor.co.jp/cgi-b..._ID=rs_775vcwc

popular choices are:
A) dewalt 12volt or dewalt 14volt or dewalt 18volt
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All three motors can be run with the stock 16.8volt EVX-2 speed controller. From reports the better choice is the 14 volt (longer run times, less heat, and more speed). The 12volt is generally $20+ dollars cheaper and runs well also with slightly more torque to spare and careful speeds into the 32-36mph range but with a tendency to get hot with high gearing. Not many people have reported using the 18volt but have been reported to be slow and needing 18+ volts to reach its true potential. The 12 volt runs well and I have achieved experimental testing speeds in the 28-35mph range with higher gearing. It does tend to run hot with higher gearing but seems much sturdier than the stock 775 motor. When bashing hard it is also power hungry and will go through your batteries faster than the stock 775. With its sturdiness and its replaceable brushes ($3) it will last a long time.
Installation for the dewalt motors requires removing the dewalt motors stock pinion (use of a dremel is recommended). sanding a flat spot on the motor stem for the new pinion. installing capacitors from the connections to the motors body. drilling the summits motor heat sink screw holes a little wider to fit properly. soldering the original motor wires to the dewalt motor. some people used a spacer (big washer) between the motor and the motor mount for the pinion and spur to align properly. You could also install the pinion backwards to achieve alignment (not perfect but it works) - 2 hour job

B) Kershaw single/dual 700ho motors
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Single or Dual Brushed motors waterproof using the summits stock ESC.
The single motor is in the same family as the stock titan 775 motor but with a variation in the internal number of windings resulting in a slight increase in speed over stock. You tube videos show the summit with dual motors reaching 29 mph (close to the e revo brushed speed) with great heaps of torque. But inherently makes a heavier truck/ a higher center of gravity and shortened run times. the system consists of two motors, motor mount/support/gears and bracket to relocate the esc. Runs nearly $100. A good brushless system is only a few greenbacks away. Also note that the Kershaw motor is widely believed to be of the Mabuchi 775 family of motors as well with a slight variation in timing/turns for better performance - Also see Graupner 700 SPEED bb turbo motors

C) Brushless motors (also requires a new speed controller and usually 2.4ghz radio)
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note: brushless motors offer much better efficiency (longer run times) , most modern systems have a automatic lipo cutoff installed within the software (lipo safe), all motors are water proof (some sensored motors are not), usually the esc will not be waterproof, for a heavy truck like the summit a motor with at kv rating from 1600v - 2400kv is suggested. Lower kv motors would have more torque but less top speed, higher kv motors will have more speed but will struggle with the weight of the summit and may have a tendency to over heat. If possible avoid 550 and 540 sized motors. They will last with conservative gearing but may prove overwhelmed by the summit's weight. Attempt to acquire an esc with at least 4s input capability. Brushless appears to be the wave of the future but a good brushed system will usually make a better and more controllable crawler.
__________________________________________________ ________

-not waterproof
-must reprogram the esc each time you change battery size (ex from 4s to 6s)
it’s a short procedure but must be done for the low voltage to work properly
-Must come to a complete stop and wait one full second before going into reverse
these settings can be changed to instant reverse (no true brake) but is not very feasible

-no on board programming
it can be programmed via the transmitter but the procedure is a bit tedious
-non sensored so driving slowly may result in surging and cogging
cogging is a stuttering motion the car experiences as the esc attempts to locate the internal position of the motor
this can be alleviated somewhat with the firmware version V1.2 and driving in low gear

C-3) XERUN 150A with 2000kv motor
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+sensored controller only - the motor is not
+ 6s capable 65+mph
+can run sensored/unsensored/brushless motors, according to the owner the brushed motor capability was removed from the software due to lack of use - per company CEO.
+65+mph Many claim that this system is every bit as fast as an MMM
+can purchase a programming box for additional features

-warranty and support is suspect at times (company is located in China)
-a few reports of excess motor heat

C-4) XERUN 80A with 2200kv motor
________________________________
+sensored controller only - the motor is not
+ 4s capable 45+mph
+can run sensored/unsensored/brushless motors, according to the owner the brushed motor capability was removed from the software due to lack of use - per company CEO.
+can purchase a programming box for additional features

-warranty and support is suspect at times (company is located in China)
-a few reports of excess motor heat

C-5) Novak HV Pro
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+sensored
+4s capable
+Novak also sells a 4s system for 1/8 size trucks. Their systems are sensored and is very popular with the 1/10 rock crawling population. They have new/larger motors 5.5/6.5/7.5 that they claim can be used in large E-revo/Summit sized trucks. The kv (speed of motor) range from 3000kv for the 7.5 to 3700kv for the 5.5 motor but all of the motors are of the same 550 size with larger internal rotors. A might small for a large truck but Novak testers claim speeds up to 41mph with the 5.5 wind motor and proper gearing but warn against aggressive gearing (???) I suspect heat issues may come into play.
none of these systems are waterproof but the MMM and XErun are supposed to be "splash proof"?? - All three have been made waterproof by several individuals using "plastic dip". "corrosion x", or a waterproof container with silicone within. (check you tube)

C-6) Twin VXL
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+waterproof
+6s capable (3s+3s)
+sensored esc
+40+mph
+many people use it with the stock AM radio

-requires two motor and two speed controllers
-many people have run/tried using a twin VXL system approach (using 2 motors and 2 speed controllers out of a mini e-revo /traxxas 4x4 slash/traxxas stampede) the setup is waterproof, brushless (6s capable) and achieves speeds in the 40mph range, but many people report eventual failure due to the inability to control high temperatures. The systems are generally for use in smaller trucks. Even though many people have claimed great success in E-Maxxes - most e-revo/summit owners complain of heat issues and high failure rates. (VXL esc is sensored - the motor is not)

C-6) Kershaw Designs
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Kershaw sells the XeRun systems/motors along with combos using its own motors and its new Generation II system for 1/8 and 1/5 sized trucks. The systems are new and I have not heard much form its users. - see their website for details

C-7) Castle MM Pro / MM pro cell
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- 4s power (new edition up to 6s?), sensored
The MMM pro was generally thought to be used for 1/10 scale (smaller) trucks but the new 1/8 scale, 12lb "Savage Flux 2350 Q" is running one successfully (renamed Flux Q-Base brushless) with a 2350Kv "Flux Alpha star" motor (in unsensored mode) so here is another option. Speeds in the savage (on 4s) are reported in the 40mph range.

Notes: (stolen from Suicide Neils e-revo faq):
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100-180f is generally seen as the safe zone for motors and escs, with 135f or below being optimum. There is an old rule of thumb regarding temps which many will find handy no-doubt:

As a general rule this is fine, though it is possible to get different results depending on the esc and motors used- some motors run hot regardless, and some escs are less capable than others to deal with high current draw. It is important to choose a suitable sized and KV motor for MT use- 36-39mm diameter, and 60-80mm in length is a good guide. The KV rating will depend on your voltage, but as a general rule again:

The summit comes stock with a Dual-Servo Steering System. This system with its twin 125oz torque servos (250oz combined) does a good job of turning the wheels. But like any true craftsman "good" is never good enough. The summits stock servos (part no 2075) have 125oz of torque each, are waterproof and are fairly inexpensive, but the internal gears are plastic and are prone to strip, at times have been proven to be not so waterproof, and the 125oz of torque is eclipsed by many after market servos.
The summit steering system is equipped with a spring based "servo saver" but many summit owners are pushing aluminum wheels with 8+ inch tires. With taller and heavier wheels (especially bead locks) and when doing serious rock crawling durability and power are essential. Many people have installed a single servo set up which is common in the revo/e-revo platform. But keep in mind the revo 3.3 and e-revo are designed for racing. Their goal is faster and lighter and a bit of strength. So for them a single servo set up works well. A single servo is lighter and a fast servo can turn their little light wheels rather quickly.
The summit on the other hand has massive 7" wheels, and is not nearly as concerned about speed as it is about power and durability. With that in mind a dual servo set up (preferably aluminum to avoid flexibility) is overall stronger more stable and with dual servos, will fetch you double the power needed to twist huge wide wheels while moving at a snails pace. With that said if you run across a 400oz servo I think a single arm set up will do. A good goal when looking for a servo is:
1) torque above 200oz (the more the merrier)
2) metal internal gears
3) transit time (speed) below 0.20 sec
4) water-proof is a plus

Many people have chosen Hitec servos for just the reasons mentioned above. They are strong (some with 300+oz torque), fast, many have internal metal gears, and are said to be highly water resistant.
Also Kershaw designs servos are popular at this time - metal geared, 231oz torque, and reports of being water friendly.

But remember not all servos have the same amount of teeth/splines on their exposed gear, and may not fit the Traxxas servo horn. In this case make certain you get a servo horn that will fit your servo. Traxxas servos and horns have a 25 spline count (matching Futuba and ACE) other servos are of course usable and will probably come with the correct splined servo horn.

The summit comes stock with massive 7" Canyon
AT tires on bead lock simulated Geode wheels with 17mm hex hubs. This stock combination has very few equals when it comes to rock crawling. The tire walls are thin and very flexible, the inner foams are soft, and the tires itself is tall. A great combination for rock crawling, but not so great for general bashing and higher speed set ups. The thin walls sometimes tear easily when bashed hard and wobbles horribly at speeds over 30 mph. Popular replacement tires for the summit are just as large but usually made of a tougher material to handle hard bashing. When changing wheels it is important to get wheels which fit your hub size (17mm). Although 17mm is a common size adapters or totally different sized hubs can be place on the summit to fit a larger variety of wheels (14mm, 23mm, and 24mm).

tire notes
______________
-Although hex sizes vary (12mm, 17mm, 23mm, and 24mm) wheels that are of interest to most summit owners usually fall into one of these few categories

when choosing tires and wheels make certain they both identify with the same nomenclature or diameter.

- proline sells "40 series" sized tires and wheels, in both normal and narrow.
- RC4WD sells "4.0" size tires and wheels; these are the same size as Prolines "40 series narrow" and are generally interchangeable.
- Traxxas stock wheels for the revo and summit are "3.8" size and will not fit "40 series" nor 4.0 sized tires. There are few companies who sells 3.8 sized tires (Imex and Traxxas are among the few).
- "MT" size wheels have a diameter of 3.2 inches and fit MT or "Maxx" size tires.
- Any pre-packaged tire/wheel combination with a 17mm hex should fit the summit

Tidbits
_________
-to remove water from inside your tire
pinch your tire at the outer tread and nip 2 small holes,
WHITHIN the confines of the tread pattern, one hole at each
opposite sides of the tire.
Lay your car on its back and give it some gas
the water should centrifuge (spin) out

1. Take the tires off
2. Turn the truck upside down and take the two screws out of the top of the steering servos so the linkage is separated from the servos
3. Plug batteries in and turn on your remote and truck
4. Turn the steering trim to 0 on your remote
5. Reconnect the steering linkage to the servos making sure the wheels are as straight as possible when re-attached
6. Put the wheels back on and you’re ready to go
7. Adjust steering if needed with the steering trim on the radio to straighten the truck out

"Dig is basically controlling one axle independent of the other axle.
On a rig with clod axles, all you have to do is run an ESC to each motor, and
have a nice radio system, and you can run 4WD or control the axles
independently. Dig serves a few purposes. On the 2.2 rigs with drive shafts
(like my axial rigs) we only use dig on the rear wheels, so I'll explain that
in the most detail. With dig, we can run the vehicle in 4wd, front wheel drive
with the rear freewheeling and front wheel drive with dig (rear wheels
locked). One huge advantage of dig is with steering. Picture trying to turn a
regular 4 WD crawler in a circle, and then imagine locking the rear wheels, so
that the front wheels drive the truck and pivot around the rear axle. You're
turning radius can be cut in half. This is very useful on tight courses,
because you lose points for backing up.

Another big function of dig with with crawling obstacles. When you take a
crawler and climb something vertical, once you're completely vertical, the rear
axle wants to push under the front axle, causing the truck to flip over
backwards. When you are only pulling with the front axle, you lose this effect
of the rear axle trying to drive under the front axle and you can get the rig
much more vertical this way. You can also lock the rear axle to load the
suspension. If you're crawling a vertical obstacle and the weight of the truck
wants to flip is over, you can lock the rear tires and pull the truck up and
over the obstacle with the front tires.

There are other functions of dig but those are some of the main uses.

There are different kinds of dig setups, and those require different radios.
There are digs that connect to the transmission, like the VF (now DNA) dig,
digs that are attached to the driveshaft, and then what I mentioned about
running two motors and ESC's and controlling them separately. I haven't run a
clod based rig so I don't know a lot about how to go about setting up dig on
them the best way. I'll use the digs that I use for an example. They bolt to
the rear of the transmission, and act as a housing. Then you have a separate
servo that selects the position of the dig shaft, which goes into the unit and
makes the magic happen. For this, you have to have a three position third
channel. This is for 2WD with freewheel, 2WD with dig, and 4WD. The Nomadio and
DX3R systems have three position third channels, and you can very easily mod a
TQ3 with the correct switch. "

Please continue to add useful information to this thread. Try to be as factual, precise, and clear as possible. Attempt to keep the chatter to a minimum. Use the PM system to ask specific questions regarding members vehicles/set up. If you like it PM a moderator to sticky it. I have tried to make this posting as factual and correct as possible. I am human and I do make mistakes. If you notice one please correct me, but be polite about it.

#6 suspension (additional information - contributed by sfr4x4)
__________________________________________________
Swapping in another set of Double-Orange (stock front) springs in the rear (or even just reversing the fronts with the rears) will help reduce squatting on accelerating.

The Summit-specific springs are approx 6MM longer than the E-Revo springs (those in the 1st chart above). This means you will need to adjust the preload collars on your shocks down an extra 6mm to attain what would be the same ride height. Also, while adjusting the preload, watch that the springs don't bind up at full compression of the suspension (binding springs will lead to destroyed shock components and bent rocker arm posts). If you find the spring binding up at full compression, this would indicate a stiffer spring is needed and to back the preload off some.

Summit axles versus erevo axles:
--------------------------------------
This is for all of you guys who have broken your axles and were shocked at how much summit axles cost compared to e-revo axles ($60 vs $25).

I have been running an e-revo axle on my original summit (on the LONG DIFF overhang side) with out issues. On full compression the longer erevo shaft reaches its max with about 2mm of play remaining within the blue dust boot - but with NO BINDING (at least on mine, but the total shaft length is controlled by how far you turn the two screws on the axle carriers "knuckles" by the wheels, my screws are showing approx 4mm of thread and runs fine) SEE PICTURE

stock summit axle on the overhang diff side at full compression:

e-revo axle on a summit on the overhang diff side at full compression:

But I did some further testing, I attempted to put an erevo axle on the over hang diff side of my second summit and to my suprise the e-revo axle circular connecter was too wide to fit. The bulkhead of the summit has a "hood" above the diff (only on the overhang side) which contacts the larger e-revo connection point (SEE PICTURE). This hooded portion does not appear to do anything special and 2mm of dremel work would make it fit fine. I probably could have forced it on, but tapping it with the dremel would be a much better idea.

e-revo axle contacting the "hood" of the summit bulkhead:

So in conclusion E-revo axles are not as strongly designed as summit axles (plastic stress points and "U" pronged connections vs metal stress points and encircled connections), but the e-revo axles can withstand up to 6s lipo power on the brushless e-revo with conservative slipper set-up. AND YES THE E-REVO AXLE WILL FIT ON A SUMMIT (INCLUDING THE LONG OVERHANG DIFF SIDE) WITH SOME MINOR CORRECTABLE DETAILS.

One goal I had in designing this dual steering system was to try to stay with as many Traxxas parts as I could, so there is a bit of a mix and match from various Traxxas kits and a couple aftermarket pieces as well. I will do my best to describe and help anyone interested in setting up rear/dual steering the way I did mine with as much detail as I can. Here goes:

My design ideas came from some of the posts I had seen on these Summit boards (thanks Brasher).

I started with a servo saver from a 1/16 E-Revo (7043). Initially I had mounted it horizontally to one of my broken Summit bumper mounts. This worked out pretty good but had no protection and was not a very rigid mount, due to only having one secure mounting point.

I picked up a Revo front bumper kit (5335a) and used a drill press to drill a 3/16 hole dead center right through it.

Next I cut the tie rod mount end off of a Summit/E-Revo servo saver (5344). I then turned it sideways and drilled 2 - 3/32” holes through the side so it would mount to the 1/16 servo saver where the steel balls would normally screw on.

Using 2 - 2.5x18mm cap screws from the 1/16 servo saver kit (7043), I mounted the modified Tie-rod holder to the end of the 1/16 servo saver.

One of the things I determined through trial and error (actually made me give up on the dual steering for a while), was that I couldn't run at any speeds over about 5 Mph without losing control. I determined the cause of this problem was the rear servo saver spring being too weak and forces created by high speeds were able to overpower the rear linkage and send my Summit completely out of control, I solved this by installing a spacer(1.9mm) under the servo saver spring which is large enough to completely take all slop out of the unit, essentially it is no longer a servo saver, rather just a linkage.

I also found a consistent weak point in the Traxxas plastic 1/16 servo saver, in that the skinny arms cannot handle the force of impact from bashing. So I upgraded to a full aluminum servo saver from GPM(you still need to purchase the 7043 kit for other hardware). The GPM servo saver also has a much more rigid design making shimming the spring unnecessary as well.

That completed, I used the steel pin from the 5344 kit in conjunction with a plastic spacer to mount my modified mini servo saver through the Revo Bumper mount(the 3/16" holes take a bit of reaming to get the pin through, but make for a nice tight fit). A 3x25 mm button head screw from the 5344 kit with a washer on each end and a 3mm nylock nut work well to keep the pin in place(make sure the screw is pushed through from the end that mounts to the chassis

The next step was to build a servo mounting plate that would fit between the rear body mount posts and was strong enough to support a servo and rigid enough to stay stable. I used a piece of flat 1/4" thick plastic which I transformed by cutting, drilling and using a bench grinder.

The servo I am currently using is a Hi-Tec HS-7955TG. I had initially used a spare Traxxas 2075 servo but found it was not strong enough.

With the Hi-Tec servo mounted behind the mounting plate it makes very good alignment with the custom mounted servo saver.

In order to have sufficient strength, even using the stock plastic servo saver from the 7043 kit, dual tie rods are required, if you like to bash hard however, I recommend the complete aluminum GPM part listed above. I have used one of the included 2 sided servo horns from the Hi-Tec kit (if using different servo, you may have to improvise here)

I then used 2 tie rod links borrowed from my rustlers, this would be most easily purchased as trx # 3737 or other 39mm turn buckles (2 required).

In order to install the rod links both the servo horn and servo saver need to have the holes enlarged to fit the 3mm screws used to attach the larger steel balls used by the 3737 tie rods. Because the servo does not line up in the center of the chassis like the servo saver does, the tie-rods will need a slightly different adjustment from each other. ***CAUTION*** do not attempt to use different holes in the servo horn to make the tie-rods visually line up as this will change the rates at which each rod moves and will cause binding/breakage.

Spacers also need to be installed behind the tie rod steel balls at the servo horn end to create enough clearance for the linkage to work.

At this point you will notice when compressing the rear suspension, the rear toe angle will change very abruptly from toe out to toe in. In order to fix this condition you will need to remount the upper pillow ball into the front most hole of the rear upper A-arm.

This means the rear alignment will need to be readjusted back to stock setting as per the manual, I do however recommend applying downward pressure on the rear springs when making these adjustments, I recommend this to simulate the famous Revo chassis squat, because it is most important for the alignment angles to be as close to factory as possible when under hard acceleration and nearing top speed.

Here is the finished project(as far as hardware goes)

Some of you that take on this project may stop here and enjoy your 4 Wheel steering by simply plugging the rear servo into a "Y" harness connected to either of the existing steering channel or the open channel 1 location if you have changed over to a single front servo system.

END QUOTE

The original thread goes on to discuss the Punk RC Dual Steering Computer and upgrade to the radio system - NNNNNIIIICCCCEEEE

Note: This is not my work all praise, glory and props (along with technical questions should be PM'd to

so since you are the expert here im hoping you will be able to answer this question for me. is it possible to put the summit locking t diffs into an e revo? if it is at all possible what types of modifications are needed to make it fit into the e revo?

QUOTE"At this point you will notice when compressing the rear suspension, the rear toe angle will change very abruptly from toe out to toe in. In order to fix this condition you will need to remount the upper pillow ball into the front most hole of the rear upper A-arm."END QUOTE
While I was messing around in my garage I came up with an almost identical rear steer setup and it never occurred to me to try remounting the upper pillow ball into the front whole of the upper A-arm, I did however find that if I switched the axel carriers from left to right and vice versa (so they are upside down with the screw going in from the bottom) it makes the tie rod line up with the rear servo saver better and also helps to reduce the toe angle changing as the suspension goes up and down.

OUAW! Thank you so much for the time invested in creating this topic. This is extremely interesting to me, I had many questions but I think finally that I'll find the vast majority of replies in this topic.

1) The "how to increase steering angle" link (in the STEERING section) is invalid... I'd love to find the original thread it pointed to, and get a little more steering from my summit. I'm guessing the link became invalid from the forum address switch...

2) There is a how-to on how to reduce tranny gear slop in low gear here : http://www.rccrawler.com/forum/gener...mit-trans.html It would be great to add this to the FAQ, either just by linking directly, or copying the contents into this thread (One should ask permission to do so and give credit where credit is due, of course)

1) Cleaned the dirt off
2) Took the rings off
3) Cleaned more dirt off
4) Sprayed it down with yellow cap oven cleaner
-Used WalMart brand first...
did not get all the chrome off, but could be due to my impatience (2 hours)
-Bought a can of the real thing...
Easy Off with the yellow cap then sprayed them down and left them overnight
I did reapply a few times during the night
5) Hosed them down
6) Picked at a few spots with a tooth pick
7) Washed them with soap and water in the bath tub
8) Let them dry outside
9) Installed the rings

Tra2244 2.4ghz radio 4channel, tra2217, tra2218x reciever issues!!!!

I have had this radio TRA2244 2.4GHZ which I bought 2years ago and tried to bind it with receiver TRA2218X,
at the time it did not work so I gave up on it. So I got a hair up my *** and tried to figure it out again and called the LHS and was told TRA2217 was the one to get so I try that and still it will not bind regardless of what I try. is the receiver I need to try is TRA2218? that is the only one left. I also tried to bind TRA2238 2.4GHZ Radio for my Rustler VXL with the TRA2217 and that did not work either, but that could be the wrong pair as well any help would be great.